1.\" Copyright (c) 2002-2004 Tim J. Robbins 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd April 8, 2004 28.Dt MBRTOWC 3 29.Os 30.Sh NAME 31.Nm mbrtowc 32.Nd "convert a character to a wide-character code (restartable)" 33.Sh LIBRARY 34.Lb libc 35.Sh SYNOPSIS 36.In wchar.h 37.Ft size_t 38.Fo mbrtowc 39.Fa "wchar_t * restrict pwc" "const char * restrict s" "size_t n" 40.Fa "mbstate_t * restrict ps" 41.Fc 42.Sh DESCRIPTION 43The 44.Fn mbrtowc 45function inspects at most 46.Fa n 47bytes pointed to by 48.Fa s 49to determine the number of bytes needed to complete the next multibyte 50character. 51If a character can be completed, and 52.Fa pwc 53is not 54.Dv NULL , 55the wide character which is represented by 56.Fa s 57is stored in the 58.Vt wchar_t 59it points to. 60.Pp 61If 62.Fa s 63is 64.Dv NULL , 65.Fn mbrtowc 66behaves as if 67.Fa pwc 68was 69.Dv NULL , 70.Fa s 71was an empty string 72.Pq Qq 73and 74.Fa n 75was 1. 76.Pp 77The 78.Vt mbstate_t 79argument, 80.Fa ps , 81is used to keep track of the shift state. 82If it is 83.Dv NULL , 84.Fn mbrtowc 85uses an internal, static 86.Vt mbstate_t 87object, which is initialized to the initial conversion state 88at program startup. 89.Sh RETURN VALUES 90The 91.Fn mbrtowc 92functions returns: 93.Bl -tag -width indent 94.It 0 95The next 96.Fa n 97or fewer bytes 98represent the null wide character 99.Pq Li "L'\e0'" . 100.It >0 101The next 102.Fa n 103or fewer bytes 104represent a valid character, 105.Fn mbrtowc 106returns the number of bytes used to complete the multibyte character. 107.It Po Vt size_t Pc Ns \-2 108The next 109.Fa n 110contribute to, but do not complete, a valid multibyte character sequence, 111and all 112.Fa n 113bytes have been processed. 114.It Po Vt size_t Pc Ns \-1 115An encoding error has occurred. 116The next 117.Fa n 118or fewer bytes do not contribute to a valid multibyte character. 119.El 120.Sh ERRORS 121The 122.Fn mbrtowc 123function will fail if: 124.Bl -tag -width Er 125.It Bq Er EILSEQ 126An invalid multibyte sequence was detected. 127.It Bq Er EINVAL 128The conversion state is invalid. 129.El 130.Sh SEE ALSO 131.Xr mbtowc 3 , 132.Xr multibyte 3 , 133.Xr setlocale 3 , 134.Xr wcrtomb 3 135.Sh STANDARDS 136The 137.Fn mbrtowc 138function conforms to 139.St -isoC-99 . 140